Bayesian credible interval construction for Poisson statistics

The construction of the Bayesian credible (confidence) interval for a Poisson observable including both the signal and background with and without systematic uncertainties is presented. Introducing the conditional probability satisfying the requirement of the background not larger than the observed events to construct the Bayesian credible interval is also discussed. A Fortran routine, BPOCI, has been developed to implement the calculation.     

煤气火焰传播规律及其加速机理研究

研究了煤气/空气预混气在两端封闭管道中的火焰传播加速现象和管道中有无障碍物时火焰的加速机理,认为火焰加速是由于火焰前未燃气体被前驱压缩波加热和障碍物诱导的湍流区对燃烧过程的正反馈造成的。实验结果表明,障碍物存在时,最大爆炸压力可提高20%,与理论计算一致;火焰传播特性随煤气浓度的变化而改变;障碍物阻塞比对火焰的速度和压力都有一定影响。     

放电型高增益KrF激光器非稳腔的研究

给出了放电型高增益非稳腔KrF激光器具有衍射极限的激光模式建立的时间与非稳腔放大率和腔长之间的关系。实验对放大率M=8,腔长L=1.75m和放大率M=13.3,腔长L=1.85m的正支共焦非稳腔在不同增益下输出光的发散角进行了测量。充电电压为30kV,发散角分别是39倍衍射极限和33倍衍射极限。当充电电压降至26kV,即降低腔内介质的增益时,它们的发散角分别是20倍和5倍衍射极限。表明了具有衍射极限的模式建立时间受放大率、腔长以及饱和效应的影响。要得到衍射极限光,其衍射极限光的建立时间必须小于饱和时间。     

Determination of hydroxyl radical in Fenton system

Under visible light illumination,2,3-diaminophenazine(DAPN) was generated from the oxidation of o-phenylenediamine (OPDA) in Fe~(3+)/H_2O_2 solution.Hydroxyl radical(~·OH) produced in this system was determined by directly measuring the concentration of DAPN.In comparison with the traditional methods,the determination is more accurate and simple.     

皮秒微脉冲电子束团诊断

介绍一种基于皮秒扫描相机的微脉冲电子束团诊断系统和实验方法。该系统具有很高的灵敏度、皮秒的时间分辨能力和机动灵活的特点,满足射频直线加速器和储存环上电子束团诊断的要求。在我国,我们首次利用该类系统测量了北京正负电子对撞机(BEPC)储存环中脉冲电子束团的波形和初步测量了北京自由电子激光装置射频直线加速器的微脉冲电子束团的时间分布。     

Rare semileptonic decays of heavy mesons in the heavy quark limit

We study the branching ratios of D^＋ → D^0e^＋ν, Ds^＋ → D^0e^＋ν, Bs^0→B^＋e^-^-ν, Ds^＋→D^＋e^-e^＋ and Bs^0→B^0e^-e^＋ rare semileptonic decay processes, which are induced by decays of light quarks, the heavy quarks remain unchanged. The branching ratios of these decay processes are estimated in the heavy quark limit and with SU（3） flavor symmetry. We find that the decay rates are very tiny in the framework of the Standard Model. We also estimate the sensitivities of the measurements of these rare decays at the future experiments, such as BES-Ⅲ, super-B and LHC-b. Observations of these decays may shed some light on new physics beyond the standard model.     

Study of charmonium(-like) states via ISR at Belle

The cross sections for e⁺e－→π⁺π^－J/ψ, π⁺π^－ψ(2S), K⁺K^－J/ψ, DD, D⁰D^－+π⁺+c.c., D^*D+c.c., and D^*D^* are measured using data sample collected on or near the Υ(4S) resonance with the Belle detector at KEKB. A peak near 4.25GeV/c², corresponding to the so called Y(4260), is observed in π⁺π^－J/ψ final state. In addition, there is another cluster of events at around 4.05GeV/c². Two resonant structures are observed in the π⁺π^－ψ(2S) invariant mass distribution, one at 4361±9±9MeV/c² with a width of 74±15±10MeV/c², and another at 4664±11±5MeV/c² with a width of 48±15± 3MeV/c². The rich structures observed in all these final states indicate that our understanding of the vector charmonium states above the open charm threshold is still poor, let alone the other possible dynamics such as charmonium hybrids or final state re-scattering and so on.     

CoV2O6纳米线／微米棒的制备及其在锂离子电池中的应用

采用水热法制备了纳米线／微米棒结构的CoV2O6电极材料,并探讨了纳米线／微米棒的形成机理．通过XRD、BET、SEM、TEM／HRTEM等测试手段对合成产物的结构、形貌、组成、表面性质进行了表征,结果表明,水热条件例如反应温度、反应时间对于产物的结构和形貌起关键作用．在220℃,水热反应1h可以得到直径为60nm的CoV2O6纳米线,而在220℃,水热反应6h可以得到直径10μm的CoV2O6微米棒．研究了CoV2O6纳米线／微米棒作为锂离子电池负极材料的电化学性能,结果显示,与CoV2O6微米棒相比,CoV2O6纳米线具有高的初始放电容量（1235mAh/g）和较好的循环稳定性,CoV2O6纳米线有希望作为锂离子电池的负极材料．     

First total synthesis of two nematicidal prenylated flavanones

The total synthesis of(±)-8-(3-methylbut-2-enyl)-2-phenyl-2,3-dihydrochromen-4-one and(±)-2-(4-hydroxyphenyl)-8-(3- methylbut-2-enyl)-2,3-dihydrochromen-4-one was first achieved through C-prenylation,protection of phenolic hydroxyl group, aldol condensation,cyclization and deprotection starting from cheap benzaldehyde,4-hydroxybenzaldehyde and 2-hydroxyacetophenone, with total yield of 20 and 16.3%.All structures of new compounds were confirmed by IR,~1H NMR and MS.     

Beam-loss driven injection optimization for CSNS/RCS

This paper summarizes the painting injection optimization for the Chinese Spallation Neutron Source （CSNS） ring. This optimization focuses on two main design goals： the lower beam loss and a spacecharge tune shift low enough to avoid strong resonances. Finally, the 3-D particle tracking is performed and we get some important results about the beam properties and beam loss.